Bag-tube end-opening means



Oct. 23, 1962 L. R. WELLMAN TUBE END-OPENING MEANS BAG 3 Sheets-Sheet 1 Filed May 4, 1959 JNVENTOR. LESTER R. WELLMAN BY ATT'YS Oct. 23, 1962 L. R. WELLMAN 3,059,550

BAG-TUBE END-OPENING MEANS Filed May 4, 1959 3 Sheets-Sheet 2 FIG. 2

4+- INVENTOR; LESTER R. WELLMAN flw w im ATT'YS Oct. 23, 1962 L. R. WELLMAN 3,059,550

BAG-TUBE END-OPENING MEANS Filed May 4, 1959 3 Sheets-Sheet 3 INVENTOR: LESTER R. WELLMAN ATT'YS United States Patent 6.

3,059,550 BAG-TUBE END-OPENING MEANS Lester R. Wellman, 110 Lakewood, Highland Park, Ill. Filed May 4, 1959, Ser. No. 813,038 Claims. (Cl. 9329) (Filed under Rule 47(h) and 35 U.S.C. 118) This invention relates to a mechanism for opening the ends of tubular bag-stock preparatory to a subsequent forming of a closed bag end on an automatic bag making machine.

The main objects of this invention are to provide an improved form of mechanism for opening the ends of tubular bag-stock as it passes through the machine preparatory to a subsequent forming of the bag bottom; to provide an improved mechanism of this kind for laying one of the two sides of flat tubular bag-stock back upon itself at a predetermined distance inwardly of the advancing end of the bag-stock and simultaneously folding inwardly and flattening down lateral portions of the stock, all preparatory to a subsequent forming of a closed bag bottom of predetermined character; to provide an improved bag-stock end-opening mechanism of this kind in which the end-opening and folding-over parts of the device are readily adjustable to accommodate varying widths of bag-stock and/or to form varying sizes of bag bottoms; and to provide an improved adjustable bag-stock end-opening mechanism which is simple in construction hence economical to manufacture and which may be integrated with a bag making apparatus for converting fiat sheets of stock into completed closed-end bags.

A specific embodiment of the invention is shown in the accompanying drawings in which:

FIGURE 1 is a side elevation, somewhat diagrammatic, of the essential parts of a mechanism constructed in accordance with this invention;

FIG. 2 is a plan view of a portion of the machine shown in FIG. 1, taken on the plane of the line 2-2, the dot-dash outline showing the bag-stock end opened, and the line 1-1 representing the plane on which is taken the elevational view of FIG. 1;

FIG. 3 is an enlarged end elevational view of this improved machine in the process of opening the bag-stock end, the view being taken from the right of FIG. 1;

FIG. 4 is a fragmentary detail of a form of gripper for releasably securing the bag-stock, adjacent the center of its web, to a conveyor for causing the bag-stock to move through the machine, the opened position of the gripper being shown in dotted outline; and

FIG. 5 is a perspective view illustrating a type of gripper for securing the bag-stock to the side chains of the end opening mechanism.

The essential concept of this invention involves the provision of a pair of laterally spaced shoe-plates mounted for reciprocation substantially parallel with the path of the bag-stock web, the shoe-plates being interconnected for simultaneous actuation by a cam-operated rocker arm synchronized with tube opening means and a bag-stock conveyor means, and the forward ends of shoe-plates being pivotly connected to links shiftable about fixed pivots above the shoe-plates to permit angular movement of the links in planes normal to the plane of the bagstock, between forward and rearward positions inclined to the plane of the bag-stock, whereby the advance of the tubular bag-stock with the under wall passing below the shoe-plates and the upper wall moving over the rearwardly-swingable links causes the lead portion of the upper wall of bag-stock to be folded back upon itself and lateral portions of both walls to be folded inwardly toward each other automatically and flattened against the respective walls of the bag-stock tube so that the angulated 3,059,550 Patented Oct. 23, 1962 perimeters of the folded-in lateral portions of the tube end and the opposedly-spaced end edges of the two walls assume a generally hexagonal form.

A bag-tube end-opening machine, embodying the foregoing concept, comprises a bag-stock conveyor 5, a pair of vacuum rollers 6 and 7 for initially spreading the leading end of the bag-tube, a pair of reciprocable shoeplates 8, actuated by a rocker arm 9 operated by a cam 10 and to which shoe-plates are connected folding links 11.

The conveyor 5 is of more or less conventional form and, as here shown, comprises pairs of chains 12 and 13 extending horizontally and spanning sprockets 14 and 16 secured to respective cross shafts 17 and 1 8 journaled on a suitable supporting frame, only a fragment of which is shown at 15 in FIGS. 1 and 3.

As is most apparent from FIGS. 2. and 3, the inner pair of chains 12 are located on opposite sides of the longitudinal median of the machine inwardly of the shoeplates 8, whereas the outer chains 13 are located outwardly of the shoe-plates 8 and along the lateral edges of the machine. The runs of each pair of chains 12 and 13 are horizontally adjustable toward and away from each other, transversely of the machine, for reasons which will be explained later.

The respective chains 12 and 13 mount bag-stock grippers 19 and 21 at predetermined intervals. As most clearly shown in FIG. 4, the grippers 19 on the inner chains 12 are adapted to engage the advancing edge of the lower layer of the bag-stock 20 whereas the grippers 21 on the chains 13 engage the bag-stock 20 along its lateral edges adjacently rearward of the advancing end of the bag-stock which is to be opened and folded in a manner presently to be explained.

Grippers 19 for this purpose may be of any suitable form. In FIG. 4 is illustrated a form involving a clamp plate 22 on the leading edge of which is mounted a clamp arm 23 arranged to pivot about a horizontally transverse pintle 24, the clamp plate and clamp arm comprising opposed rearwardly opening jaws between which the leading edge of the bag-stock is gripped. The clamp plate 22 is fixed to the respective chain 12 and the clamp arm 23 is normally heldin closed position by a coiled spring 25 surrounding the pintle 24. As shown in FIGS. 3 and 4, the clamp arm 23 is provided with a pair of laterally spaced operating arms 26 which eXtend forwardly and downwardly from the pintle 24, one on each side of the chain 12, and each of these operating arms carries an end roller 27 positioned to engage the hubs 16 and 14' which project from each side of the sprocket 16 and 14 respectively. Thus the jaws of the grippers 19 are normally closed, but upon reaching the ends of the chain run the operating arms 26 engage the respective sprocket hubs causing the arms to be swung backwardly, to the dotted position shown in FIG. 4,- to open the gripper jaws for insertion or release of the bag-stock web according to the end of the machine where the gripper opening action occurs.

The grippers 21 on the outer chains may also be of a conventional type suitable for continuous bag making machines and in the for-m shown are slide clamps, mounted transversely of the conveyor chains, arranged to engage and grip the lateral margins of the bag-stock web for pulling the bag-stock through the end opening and folding operation. As shown, the gripper 21 comprises a bottom plate 28, secured medially on the chain 13 so as to extend crosswise thereof, and a slide plate 29 mounted parallel with the bottom plate 28 and slidably retained thereon by means of fingers 30 projecting inwardly from each side of the plate 28 and overhanging its top surface in spaced relation therefrom. The slide plate 29 has an upwardly bowed leaf spring 31, secured at its rearward end on the upper surface of the slide plate, and of sufficient width to extend laterally beneath the forward pair of fingers 30.

The fingers 30 are sufiiciently spaced from the surface of the plate 28 to allow the slide plate '29 to float between the fingers and the plate 28 when the slide plate is in the retracted position shown in FIG. 5. When the slide plate is moved forwardly, however, the bowed portion of the spring 31 passes beneath the forward pair of fingers 30 and forces the slide plate downwardly against the bottom plate 28. Thus with the grippers 21 coming up from beneath the bag-stock web 20, at the entering or left hand end of the machine as shown in FIG. 1, the bag-stock will first be engaged by the bottom plate of the gripper and, laying flatly thereon, will be positioned to be clamped by the slide plate 29 when it is moved forwardly, or to the left in FIG. 5.

Actuation of the slide plate 29 of the gripper 21 is accomplished by means of a roller 32, projecting perpendicularly from the rearward bottom end surface of the plate 29, which roller is engaged by appropriately located cam bars 33 and 34 adjacent the entering and leaving ends of the machine respectively, as shown in FIG. 2. At the entering end the cam bars 33, upon engaging the roller 32, cause the slide plate to move inwardly over the paper web 20 to clamp it against the bottom plate 28. At the leaving end of the machine the cam bars 34 cause the slide plate to move outwardly to release the web 20, at which time the grippers 19 are also opened to release the web as before mentioned.

The pneumatic rolls 6 and 7 are also more or less conventional devices for preliminarily opening the forward or leading end of the tubular bag-stock and as shown in FIG. 1 comprise a pair of cylinders mounted on parallel horizontal shafts 35, one above the other, so as to engage and pull the bag-stock between them in the direction toward the folding shoes 8. These rollers 6 and 7 here are shown equipped with vacuum cups 36 so exposed on the peripheries of the respective roller that as the advancing end of the bag-stock 20 passes beyond a vertical plane through the roller axes the upper layer 37 of the bag-stock is carried uparound the top roller 6 while the lower layer 38, rearwardly of the grippers 13, is held down until it passes beyond the edge 39 of a suitable table structure 40 which extends through the machine between the chains 12 and 13 (FIG. 1). Obviously, these cups 33 are connected through the hollow shafts 35 to a source of vacuum and cont-rolled by suitable 'mechanism for cutting on and off the vacuum, neither of which are shown here.

The shoe-plates 8, here are shown as inwardly facing angle bars secured to slide shafts 41 reciprocable parallel with the chains 12 and 13 in bearings 42 which are suspended from support plates 43 by pendant arms 44. In length the shoe-plates 8 are somewhat less than that of the conveyor 5, however these shoe-plates do extend for an appreciable distance parallel with the conveyor chains and suflicient to accomplish the end folding of the bag-stock, as will be hereafter described, as indicated in FIG. 3. A pair of these shoe-plates 8 are secured to the respective shafts 41 by short clamp blocks 45 and 46, adjacent the opposite ends of the shoe-plates 8, so as to dispose the shoe-plates 8 closely parallel with the plane of movement of the bag-stock 20. The shoe-plates 8, in their most advanced positions, have their forward ends juxtaposed to the bag-end-opening rolls 6 and 7 a predetermined distance forwardly of the fixed pivots 47 of the hereinafter described links 11. From such advanced position the forward ends of the shoe-plates 8 are shifted an equal distance rearwardly of the link pivot 47, to eifect the desired opening and folding of the bag-stock end, as shown in dotted outline in FIG. 1.

The slide shafts 41, at their rear ends, mount collars 48 to which is slidably connected a transverse tie rod 49 so that the shoe-plates 8 are simultaneously reciprocated by the single, cam-actuated, rocker arm 9, as presently will be explained.

The support plates 43, from which the shaft bearings 42 are suspended, are slidably supported, adjacent their opposite ends, on suspension rods 50 suitably secured to the machine frame to permit horizontal adjustment of the lateral spacing of the shoe-plates 8 to accommodate varying widths of bag-stock. Such adjustment of th plates 43 is effected by a screw shaft 51, also journaled adjacent its ends on the machine frame, which has right and left-hand threads 52 and 53 extending through respectively threaded openings in the support plates 43. Hence, a turning of the screw shaft 51 shifts the support plates 43 in opposite directions on the suspension rods 50.

The rocker arm 9 is fulcrumed on a bearing 54 secured at the rear end of one of the support plates 43. At its lower end the rocker arm 9 is slidingly connected to a pivot pin 55 attached to one of the blocks 46 mount ing the shoe-plates 8 on the slide shafts 41. At the up per end, the rocker arm 9 mounts a roller 56 running In an eccentric groove 57 in the cam 10.

The cam 10 is also slidingly mounted on a cam drive shaft '58 journaled in bearings 59 mounted on the machine frame 15. The cam 10 has to be slidably keyed on the shaft 58 to accommodate any transverse adjustments of the shoe-plates 8 by means of the screw shaft 51. As is most clear-from FIG. 3, the cam 10 may be slidably keyed to the shaft 58 in an elongate key way 60 and secured by a set screw 61.

The links 11 are hinged by pins 62 at their lower ends adjacent the forward ends of the respective shoe-plates 8. The upper portions of the links 11 are formed with slots 63 slidable on the respective hinge pins 47 secured to the forward ends of horizontally extending arms 64 which are secured to the pendant arms 44 intermediate the bearings 42 and the support plates 43, as shown most clearly in FIG. 1.

The links 11, being so connected to the shoe-plates 8 and the arms 64, are caused to swing between forwardly and rearwardly inclined positions (indicated respectively by full and dotted outlines in FIG. 1) with the reciprocation of the shoe-plates 8. It is this synchronized retraction of the shoe-plates 8 and the rearward swinging of the links 11 that completes the opening and folding 'back of the bag-stock end, and the folding-in of the lateral end portions, as it advances beyond the rollers 6 and 7, as presently will be described fully.

It will be understood, of course, that suitable motor driven mechanism, indicated generally at M and D in FIG. 2, will be connected to drive and synchronize the speeds of the conveyor 5, the rollers 6 and 7, and the cam 10 to feed the bag-stock in timed relation with the conveyor grippers and the operation of the folding shoes. Furthermore, it will be understood that this machine may be used either as an independent unit or integrated as the bag-stock end-opening station in 'a bag-forming apparatus, wherein sheets of paper are first folded to form tubular bagstock which then is severed into bag lengths and, after having the one end opened and formed as herein shown and described, are appropriately sealed to form a closed bag end of the satchel bottom type. A an integrated component of a bag making machine the end opening mechanism may be driven from the same power source as the main machine.

The operation of this improved form of bag-stock endopening machine-used in either of the before-mentioned Ways-is substantially as follows:

The leading end of the tubular bag-stock 20 enters the end-opening machine between the vacuum rollers 6 and 7 and as the bag end passes beyond the bight of the rollers the upper and lower walls of the bag tube are held against the respective roller surfaces by means of the vacuum cups 36, the lower bag wall being held by the roller 7 just sufliciently to feed it over the edge or lip 39 of the table surface 40 and pass it beneath the forwardly projected ends of the shoes 8. The upper wall of the bag tube, however, is held by the roller 6 for a time suflicient to feed the opened end of the bag over the links 11, after which it is released. Appropriate means not shown, but well understood in this art, are provided to control the holding action and the timing of the vacuum system.

As the hinged ends of the shoes 8 and links 11 are entered into the opened end-of the bag tube, presented by the vacuum rollers 6 and 7, the center grippers 19 on the conveyor chains 12 close on the leading edge of the bottom bag-tube wall and firmly connect the bag tube to the conveyor system, the chains 12 being so timed relative to the feed of the bag tube from the rollers 6 and 7 as to be properly positioned to receive the leading end of the tube. At a predetermined time afterward the grippers 21 on the side chains 13 come into position to clamp the side edges of the bag tube just rearward of the desired transverse fold line A, as shown in FIG. 2, the chains 13 moving at the same speed as the chains 12 and the grippers 21 being located the proper distance behind the grippers 19.

At the appropriate time when the opened end of the bag tube is fed forwardly over the links 11, so as to be engaged by the links, the slide rods 41 are shifted rearwardly by the lever arm 9 and cam 10, at substantially the same speed as the conveyor chains, and the links 11 are thereby caused to swing rearwardly on their fixed pivots 47 to the rearwardly inclined position shown in dotted outline in FIG. 1, the shoes 8 likewise moving rearwardly at the same time. This turns the upper wall of the bag tube backwardly a suflicient distance that, as the bag tube is pulled beneath the rearwardly positioned links and shoes by the conveyor chains, the backward folding of the turned upper bag wall upon itself is completed by passage beneath the shoes 8. Meanwhile the sides of the bag tube, outwardly of the shoes 8 are automatically folded inwardly and flattened to a triangular shape, indicated at B in FIG. 2, centered on the fold line A.

During this operation the links 11 have swung through an angular movement of about 90 at which point, after a slight apparent pause due to the harmonic motion of the lever arm 9 under the action of the rotary cam 10, the shoes 8 and the links 11 begin their return movement toward their initial forwardly projected position ready to receive and act upon the leading end of the next succeeding bag-tube section. Meanwhile the open-ended first bag-tube section, having reached the end of the conveyor 5, is released automatically from the grippers 19 and 21, in the manner before explained, and is delivered by the machine to the next operation which is performed by further mechanism that is not a part of the present invention.

Adjustment of the components of the improved machine herein described, to accommodate bag tubes of various widths and depths of end fold, is made by shifting the folding shoes and links toward or away from each other by means of the adjusting screw 51 and according to the desired form of the end product. For a given tube width deeper end opening folds are had by moving the folding shoes toward each other, and shallower foldsfor a wider expanded bag-are accomplished by moving the shoes away from each other. For various widths of bag-tube stock, the conveyor chains 13 are adjusted toward or away from the center of the machine on the respective shafts 16 and 17.

The main advantages of this invention reside in the improved and simplified construction of the machine whereby a fully automatic end opening operation on tubular bag-stock is performed with a minimum of apparatus and moving parts; in the arrangement of the machine components whereby full and ready adjustability is bad to accommodate a wide range of tube-stock widths; and in the construction of the machine whereby it can 6 be readily incorporated into existing bag making machines or used independently as may be desired.

Although but one specific embodiment of this invention is herein shown and described it will be understood that numerous details of the construction shown may be alte'red or omitted without departing from the spirit of this invention as defined by the following claims.

I claim: I

1. A bag-stock end-opening machine comprising a supporting frame, inner and outer conveyors mounted on the frame and each having automatically-acting bag-stock grippers spaced therealong, the inner conveyor being positioned to have its grippers engage the advancing end of the lower bag-stock layer and the outer conveyor being positioned tohave its grippers engage the edges of the bag-stock rearwardly of the advancing edge, a, pair of shoe-plates mounted on the frame for-reciprocation closely parallel to the plane of movement of the bag-stock, there being one of said shoe-plates on each side of the inner conveyor, links hinged to the forward ends of the shoeplates and pivoted above the same intermediate the opposite limits of movement of the forward ends of the shoeplates for swinging between forwardly and rearwardly inclined positions during the reciprocative movement of the shoe plates, means located adjacent the forward ends of the shoe-plates for separating the upper layer of the bag-stock from the lower layer and guiding the lower layer under the shoe-plates and the upper layer above the hinged connection of the shoe-plates and links, a rocker arm fulcrumed on the frame and connected to the shoe-plates, and a cam journaled on the frame and connected to actuate the rocker arm and to synchronize the reciprocation of the shoe-plates with the movement of the conveyor whereby the movement of the bag-stock along the rearwardly-moving shoeiplates and rearwardly swinging links causes the upper bag-stock layer to be folded back upon itself and lateral portions of the bagstock to be folded inwardly and flattened against the bagstock by the advance thereof along the under faces of the respective shoe-plates.

2. An end-opening machine for fiat tubular bag-stock comprising a supporting frame, inner and outer conveyors mounted on the frame and each having automaticallyacting bag-stock grippers spaced therealong, the inner conveyor being positioned to have the grippers thereof engage the advancing end of the lower bag-stock layer and the outer conveyor being positioned to have its grippers engage the side margins of the bag-stock rearwardly of the advancing edge, a pair of shoe-plates mounted on the frame for reciprocation closely parallel to and above the plane of movement of the bag-stock, there being one of said shoe-plates on each side of said inner conveyor, links hinged to the forward ends of the shoe-plates and pivoted above the same intermediate the opposite limits of movement of the forward ends of the shoe-plates for swinging between forwardly and rearwardly inclined positions during reciprocative movement of the shoe-plates, means located adjacent the forward ends of the shoeplates and adapted to separate the upper layer of the flat bag-stock tube from the lower layer and guide the lower layer under the shoe-plates and the upper layer above the hinged connection of the shoe-plates and links, and means on said frame for reciprocating the shoe-plates in timed relation with the operation of said conveyor and the first named means, whereby the movement of the bag-stock on said conveyors and beneath the shoeplates and swinging links during rearward movement thereof causes the leading end of the upper bag-stock layer to be folded back upon itself and lateral portions of the leading end of the bag-stock to be folded inwardly and flattened against the bag-stock.

3. An end-opening machine for flat tubular bag-stock comprising a supporting frame, inner and outer conveyors mounted on the frame and each having automaticallyacting bag-stock grippers spaced therealong, the inner con- '7 veyor being positioned to have the grippers thereof engage the advancing end of the lower bag-stock layer and the outer conveyor being positioned to have its grippers engage the side margins of the bag-stock rearwardly of the advancing edge, a pair of shoe-plates mounted on the frame for reciprocation closely parallel to and above the plane of movement of the bag-stock, there being one of said shoe-plates on each side of said inner conveyor, links hinged to the forward ends of the shoe-plates and pivoted above the same intermediate the opposite limits of movement of the forward ends of the shoe-plates for swinging between forwardly and rearwardly inclined positions during reciprocative movement of the shoe-plates, means located adjacent the forward ends of the shoeplates and adapted to separate the upper layer of the flat bag-stock tube from the lower layer and guide the lower layer under the shoe-plates and the upper layer above the hinged connection of the shoe-plates and links, and means on said frame for reciprocating the shoe-plates in timed relation with the operation of said conveyor and the first named means, whereby the movement of the bag-stock on said conveyors and beneath the shoe-plates and swinging links during rearward movement thereof causes the leading end of the upper bag-stock layer to be folded back upon itself and lateral portions of the leading end of the bag-stock to be folded inwardly and flattened against the bag-stock, and means for adjusting the shoeplates transversely toward and away from each other to alter the dimensions of the folds in opened end of the bag-stock.

4. An end-opening machine for flat tubular bag-stock comprising, a supporting frame, a conveyor mounted on the frame for effecting the movement of bag-stock along a predetermined plane, a pair of laterally spaced shoeplates, one on each side of the longitudinal centerline of said conveyor, mounted on said frame for reciprocation parallel with said conveyor centerline above and closely adjacent the plane of movement of the bag-stock, a link hinged to the forward end of each shoe-plate and slidingly pivoted at a point above and intermediate the opposite limits of movement of the forward end of the shoeplate for swinging between alternate forwardly and rearwardly inclined positions during each reciprocation of the respective shoe-plate, means located adjacent the forward ends of the shoe-plates for separating the upper layer of the flat bag-stock tube from the lower layer and guiding the lower layer under the shoe-plates and the upper layer above the hinged connections of the shoe-plates and links, means for driving said separating means and said conveyor, and means for reciprocating said shoe-plates in unison and in timed relation with said separating means and conveyor, whereby the movement of the bag-stock on said conveyor and beneath the rearwardly moving shoeplates and rearwardly swinging links causes the upper bag-stock layer to be folded back upon itself and lateral portions of the bag-stock to be folded inwardly and fiattened against the bag-stock.

5. An end-opening machine for flat tubular bag-stock comprising, a supporting frame, a conveyor mounted on the frame for effecting the movement of bag-stock along a predetermined plane, a pair of laterally spaced shoeplates, one on each side of the longitudinal centerline of said conveyor, mounted on said frame for reciprocation parallel with said conveyor centerline above and closely adjacent the plane of movement of the bag-stock, means on said frame for supporting each of said shoe-plates independently of the other, a link hinged to the forward end of each shoe-plate and slidingly pivoted at a point on said support means above and intermediate the opposite limitsof movement of the forward end of the shoeplate for swinging between alternate forwardly and rearwardly inclined positions during each reciprocation of the respective shoe-plate, means located adjacent the forward ends of the shoe-plates for separating the upper layer of the flat bag-stock tube from the lower layer and guiding the lower layer under the shoe-plates and the upper layer above the hinged connections of the shoe-plates and links, means for driving said separating means and said conveyor, and means for reciprocating said shoe-plates in unison and in timed relation with said separating means and conveyor, whereby the movement of the bag-stock on said conveyor and beneath the rearwardly moving shoeplates and rearwardly swinging links causes the upper bagstock layer to be folded back upon itself and lateral portions of the bag-stock to be folded inwardly and flattened against the bag-stock, and means for shifting said shoe plate support means transversely of said conveyor to vary the lateral spacing of said shoe-plates relative to the said conveyor centerline.

References Cited in the file of this patent UNITED STATES PATENTS Crawford July 27, 1943 IMa 

